1 Isotonic -a muscle fiber contraction in which force production is unchanged when the muscle contracts causing movement of an external load.  Isokinetic -a muscle fiber contraction in which force production of the contraction is sufficient to overcome the external load.
HIV/AIDS. HIV Risk Behaviors. The risk of getting HIV varies widely depending on the type of exposure or behavior (such as sharing needles or having sex without a condom). Some exposures to HIV carry a much higher risk of transmission than other exposures.
The following circumstances are noted to be highly prone to the infection: 1  Unprotected anal sex is at the top of the list according to a reliable source. 2  Unprotected vaginal sex is next in line. 3  Irresponsible use of intravenous drugs has been traced to the sufficiently alarming increase of HIV/AIDS cases.